Most likely they were referring to G-force felt while going around a curve. It is calculated by taking the square your velocity divided by the radius of the curve, (V)2/R. This angular acceleration is what you feel when taking a corner in a moving vehicle, commonly referred to as centrifigual force (proper term is centripital).
If indeed it is linear acceleration similar to a jet being catapulted off of an aircraft carrier, at a constant acceleration of 1.5 G (1 G equals 32.19 ft/s2) from complete stop, it'll take 1.83 seconds to reach 60MPH (or 88 ft/s)